Breast Cancer: Blood Test Spots Wayward Tumor Cells

cp418 · June 2012

jenrio · June 2012

Thanks for the pointer! The next step is to be able to molecular characterize the CTCs (Her2, ER/PR, other receptors, mutations) and guide treatment strategies realtime and accelerate clinical trials.

This sentence gave me pause: "Of those, 15 per cent experienced a cancer relapse and 10 per cent died during the study period" in 5 years study period 2005-2010. 5 year mortality rate of about 66% among these early breast cancer patients with 1 + CTCs. This is at MD Anderson.

"For women with three or more circulating tumour cells in their blood sample, the outcomes were much worse: 31 per cent died or experienced a relapse."

This is why the research for MBC cure needs to accelerate. 20 years, the improvement in MBC mortality rate has gone from 97% to 66%. It's not "chronic" like AIDS or diabetes. AIDS or diabetes patients can expect to live a full life span. MBC is a killer with no cure. and no early stage patient is really cured till MBC has a cure.

lilylady · June 2012

My oncologist has tried the CTC test on 6 of his patients and the results were worthless. He has been to a major conference on this procedure and came away with the opinion that it needs more work before he will try ii again. Out of the 6 he sent we all came back as 0-and at least 3 of us were in active progression.

I am sure it will be a great tool i years to come but not so much right now. Also many insurance compan ies will not pay for it. Their thinking is if they pay for this expensive test will an oncologist make tx decisons based solely on the results? Or will he then order an expensive scan to confirm the problem. Therefore they are paying for 2 tests. My insurance co did pay eventually.

The onccology lab has to stock speial tubes for this and they have to be sent out. The ccompeting places selling this test have web sites where they all claim to be the ONLY place with accurate results.

I am glad you posted those sites-thank you.

jenrio · June 2012

CTC test needs special tubes and needs mixing the blood carefully after blood draw. Also it needs to be run days after the blood draw.

Also, CTC has high false-negative rate. ie, only a portion of metastatic patients get positive CTCs. The next generation of CTC test hopefully will lower that false negative rate, and become more accurate.

But for fast clinical trials, CTC can be an useful tool. Say you take only patients with 5+ CTCs, gave them experimental medicine and see whether the CTC drastically drops and stay dropped. I'm sure the doctors would say "this is not ready for prime time". Doctors can be as cautious as politicians, they may be forced to by the lawsuit/scholar culture. But hey, 10 years later when it's ready for prime time, a lot of patients would have died for want of the cure, and MBC mortality rate would drop from 66% to 50%?

Dying patients do not wait for prime time.

dlb823 · June 2012

Here's something from Dr. Susan Love that puts this news into much clearer perspective than the coverage or even the headline catching spin (i.e. Catching Wayward Tumor Cells) put on it by some health journalists and media outlets:

http://blog.dslrf.org/?p=543

jenrio · June 2012

I agree that this study is not large. But the next larger study would take another 5 years to confirm what Dr Love said "we have known" or suspected for a long time: ie, CTC is prognostic (more so than lymph node) and CTC can be used to guide treatment.

In the meantime, early stage patients are told, "So, basically, knowing that you have them will only make you worry-or worry more than you already do. " That seems a little condescending.

Knowledge is power. There are a lot early stagers can do to help reduce their chances of recurrence, say exercise and diet and stay on tamoxifen and regular checkups and watch for symptoms. Instead, they are told "you are cured, no worries" and sent away in blissful ignorance.

Breast cancer of certain types tend to come back even after 5 years (linear recurrence risk). Note that this study only covers 5 years, already 15+% of CTC+ patients had recurrence. What if the study covers 5 more years?

Dr Love mentions "A recent provocative study showed that the cells detected in the blood stream are not all of the same type as those in the tumor and so may need a different treatment than the main lesion. " The study is linked and very good read.

This is great, keep investing and keep innovating. Work things out! but patients deserve to know their own CTC data and should be trusted to do their own worrying.

Breast Cancer: Blood Test Spots Wayward Tumor Cells

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